Switch



Jah. 24, 1939. i c4 F-FORSBERG SWITCH Filed Oct. 16, 1935 4 Sheets-Sheet 2 ATTOR/V V /Nl/E/V TOR By of. FORSBERG Jam. 24, 1939.

O. F. FORSBERG SWITCH Filed Oct. 16, 1935 4 SheetS-Sheefl 3 /NVE/v TOR 0./-7 FORSBERG ATTORNEY Jan. 24, 1939. )A F, FQRS-BERG 2,144,839

SWITCH Filed Oct'. 16, 1935 4 Sheets-Sheet 4 /A/l/EA/TOR 0. F FORSBERG ATTOR/VEV Patented Jan. 24, 1939 UNITED STATES PATENT OFFiCE SWITCH Application October 16, 1935, Serial No. 45,174

13 Claims.

This invention relates to selective switches and particularly to those used in telephone exchange systems.

The objects of the invention are to simplify the construction oi selective switches, to increase the reliability ci their operation, to facilitate the assembly and replacement of their parts, to increase their wearing qualities, and to effect other improvements therein.

Various kinds of cross-bar switches have been designed heretofore. In some of these exible actuating lingers are controlled by the conjoint action of two bars to eect the closure of a contact set. In others rigid actuating devices are provided at the cross-points instead of the eX- ible lingers for controlling the Contact sets.

A feature of the present invention is a switch of this general character having rigid elements or fingers for actuating the contacts at the crosspoints and in which each ringer has one end loosely xed in a slot of the supporting member in such a way that the free end of the finger is movable in any direction about the xed end as a center. The setting oi the actuating linger is effected by the conjoint movement of the operating bars, and the linger in turn causes the closure of the contacts. The actuating linger is provided with shoulders at its Xed end which engage the supporting member and determine the normal position of the linger with respect to said member, and it is held in this position by a small helical spring. In the setting operation the finger is moved against the tension of the spring in two principal directions, and, when released, it is returned by the spring directly to its normal position since itis capable of universal movement.

This construction has the advantage that the actuating ngers are free from any inherent flexibility and do not tend to participate in a vibrating action when they are suddenly released from the oper-ated position. Also they are not liable to become bent or distorted, causing the switch to fail in its operation or to perform a false operation. Another advantage is that the actuating ngers are held in the assembled position by means of their springs alone. This facilitates the initial assembly of the parts and also the ready removal of any finger in case replacement is necessary. A further advantage is that the actuating finger can be made of relatively heavy stock, giving improved wearing qualities and longer life.

The foregoing and other features of the invention will be discussed in detail in the following specication and will be set forth in the appended claims.

In the drawings, which also constitute a part of the specification;

Fig. l is a iront plan view of the switch as a whole with certain duplicate parts broken away and removed to conserve space;

Fig. 2 is a side view, partly in plan and partly in crossesection, taken along the line 2-2 in Fig. 1

Fig. 3 is an enlarged perspective showing the contact operating mechanism located at one of the cross-points of the switch;

Fig. e is a side View showing one of the contact operating elements;

Fig. 5 is a similar view showing the element partly removed from the mounting strip that supports it;

Figs. 6 and 'lA are top views of a set of contact springs in their open and closed positions, respectively; and

Figs. 8 to l1, inclusive, are diagrams showing successive steps in the selection and operation of a set of contact springs.

This invention is applicable in general to switches of the cross-bar type in which the bars of a plurality oi sets cooperate with each other to bring about the selective operation of a desired set of circuit-making contacts. A switch of this kind is shown and described in the patent to J. N. Reynolds, 1,953,503 of April 3, 1934. In the Reynolds patent and in the switch illustrated herein the cross-bars are operated in a longitudinal or sliding movement. Other switches of this general kind make use of rotary cross-bars, and it should be understood that the present invention may also be applied to switches of this kind.

Referring now to the drawings, the frame of the switch illustrated therein comprises the upper and lower members l and 2 and the side members 3 and fi. These four members are secured to each other in any suitable manner, as by means oi welded joints.

rThe contact sets and the contact operating mechanisms are mounted in units on the vertical mounting plates 5, 6, l, 8, etc. These plates are secured by means of screws 9 to the upper and lower frame members l and 2. The number of these vertical units is Variable and depends upon the desired capacity of the switch. One convenient capacity for switches of this kind is aiorded by providing ten of these vertical units. For

larger switches as many as twenty vertical units may be used. The Contact bank which is formed by the spring contacts carried by the several mounting units may be considered as divided into two multiples, a horizontal multiple and a vertical multiple. The horizontal contact sets appearing at successive cross-points along a horizontal row may be multipled together by means of strap wires which are soldered to the terminals provided at the rear of the switch, as seen in the several gures. The cooperating vertical contacts appearing at successive cross-points in a vertical row may be formed integrally with each other by stamping them from metal sheets, and each such multiple strip may be provided with a terminal projecting to the rear of the switch for external connections. These latter connecting terminals are also illustrated in the drawings, and they are well understood in the art. To effect a connection between the horizontal and vertical contact springs at any particular crosspoint, it is necessary to select the cross-point and to move the springs into engagement with each other. This is accomplished by means of the contact selecting andoperating mechanisms which will be described hereinafter. Before taking up the operating mechanisms, however, a description will first be given of the cross-bars which control the selection and operation of these mechanisms.

The cross-bars of the switch comprise two sets, the vertical or select bars I6, II, I2 and I3, etc. and horizontal or actuating bars I4, I5, I6, I1, I3, etc. These vertical bars are operated in a longitudinal manner by corresponding vertical magnets I9, 20, 2I, 22. The vertical bar II, for instance, is suspended on the extension 23 of the armature 24 of the corresponding vertical magnet 20. The lower end of the bar I I is fixed for movement up and down in a slot in the guide plate 25. The vertical magnets are mounted, respectively, on the vertical mounting plates. For example, the magnet I9 is mounted on the bracket 26 which is integral with the vertical mounting plate 5. The same is true of the remaining vertical magnets. The horizontal bars I4, I5, I6, etc., are also mounted for longitudinal movement by their corresponding horizontal magnets 21, 28, 29, etc. The bar I4, for example, is supported at one end on the extension 36 of the armature of magnet 21, and at the other end this bar is fixed for slidable movement in a guide plate 3I secured to the frame member 4. Similarly, the remaining horizontal bars are mounted for longitudinal movement. Suitablesprings, not disclosed, are provided for restoring the bars to their normal positions after they have been operated by the horizontal magnets. The number of horizontal bars may be varied and will be determined by the desired capacity of the switch. A convenient number of horizontal bars is ten for switches of this kind.

Coming now to the contact operating mechanisms, these may be more clearly understood from a reference to Figs. 2 to '7. The essential element of the contact operatingmechanism is a flexibly mounted rigid operating linger. Each set of contacts at the several cross-points of the switch is equipped with one of these lingers. In Fig. 2 four of these operating fingers, 32, 33, 34, 35, located in the same vertical row, are illustrated. These four operating iingers, and others not shown in the drawings, are associated with the vertical bar II and with the corresponding vertical row of contact sets. They are supported by a strip 36 which is bolted to the vertical supporting plate 6. The operating finger 32, for

instance, has one of its en'ds tapered and formed to present shoulders 31 and 38, as seen more clearly in Figs. 4 and 5. When in position the nger 32 rests in a slot in the strip 36 with the shoulders 31 and 38 bearing against the strip 36 and firmly held in position by the retractile spring 39. The receiving slot for the iinger is sufficiently large to permit the finger to move freely in all directions about the iixed end as a center, the retractile spring 33 always acting to restore the nnger to the normal position shown in Figs. 2 and 3. The free end ofthe finger 32 is provided with anotch 40 which embraces the corresponding horizontal bar I4. When in its normal position as seen in Fig. 3, the linger 32 rests lightly on the bottom of notch r4I in the guide member 25 and lightly on the integral shoulder 42 formed on the vertical bar II. Moreover, with the iinger 32 in its normal position it rests on the horizontal bai` I4 adjacent the corresponding projection 43 on said horizontal bar.

The set of contact springs located at the point of crossing of the vertical bar II and the horizontal bar I4 and which are controlled by the operating linger 32 at that cross-point comprise a number of movable springs 45 and an equal number of cooperating stationary springs 46. The movable springs 45 are the ones which have their terminals at the rear of the switch and which are multipled to other movable springs in the same horizontal row. The stationary springs 46 may, as hereinbefore explained, be multipled with other springs in the same vertical row. The movable springs 45 are secured to a movable insulating plate 41 so that any movement imparted to theV plate causes all of the springs 45 to move in unison therewith. The stationary cooperating springs 46have their free Vends secured to the stationary insulating plate 48. The end of the movable plate 41 is so located with respect to the operating nger 32 that, when the iinger 'is raised vertically from its normal position and is then moved horizontally, said finger engages the plate 41 and forces the movable springs into contact with the corresponding stationary springs. When the elements are in their normal position, however, as seen in Figs.'

2 and 3, the finger 32 lies somewhat below the end of the plate 41 so that any movement of the nger in a horizontal direction merely causes it to pass in under the plate 41 without causing any movement of the contact springs.

A description will now be given of the manner in which the different parts of the switch function to selectively operate a desired set of crosspoint contacts. Assume for this purpose that it is desired to close the contact springs 45 and46 at the cross-point with which the operating iinger 32 is associated. To this end the vertical magnet 23 is rst energized to lift the vertical bari I. The upward movement of the bar I I causes the shoulder 42 to lift the operating nger 32 against the tension of its spring 39 to a position (Figs. 4 and 9) where the finger 32 lies opposite the end of the insulating plate 41. In executing this movement the finger 32 pivots about its upper shoulder 31 which is held by the spring 39 rmly against the supporting plate 36, the free end of the finger describing a small vertical arc. Following this the horizontal magnet 21 is energized to draw the horizontal bar I4 toward the left as seen in Figs. 1 and 3. As the bar I4 moves toward the left, the projection 43 thereon encounters the free end of the finger 32 and swings the nger in a horizontal arc about its fixed end as a pivot. This horizonil (l tal tilting movement of the finger 32 results in a further tensioning of the spring 39 which tends to withdraw the finger back to its normal position. As the iinger 32 is thus moved by the bar I4, it engages the insulating plate 41 and forces the movable springs 45 into engagement with the Stationary springs 45. This position of the parts is illustrated in Figs. 'T and 10. Finally the vertical magnet 2Q is deenergized, permitting the vertical bar II to restore to its normal position. The continued energizaton of the horizontal magnet 2l holds the horizontal bar I4 and the iinger 32 against the plate 4'I to maintain the closed set of contacts in its operated position. This condition is illustrated in the diagram oi Fig. 11.

To release the closed set of contacts, it is only necessary to deenergize the magnet 2'I, permitting the horizontal bar I4 to restore to its normal position. When the bar I4 restores, it releases the finger 32, and the spring 39, which has been tensioned by both the vertical and horizontal movements of the ringer, now restores the finger to its normal position in its slot in the supporting strip 35.

Each oi the several cross-points in the switch is similarly equipped with an operating linger; and each of the vertical bars corresponding to a particular vertical row of contacts is provided with a shoulder, such as the shoulder 42, for raising the corresponding finger; and each of the horizontal bars relating to a horizontal row of contacts is provided at every cross-point with a projection, such as the projection 43, for imparting a horizontal movement to the corresponding operating finger. Whenever a vertical bar is raised, it raises all of the operating fingers which at the time are in their normal positions. However, since the operation of the vertical bar is usually followed by the operation of a. single horizontal bar, only one of these elevated fingers becomes effective to close a set of contacts, and the remaining fingers associated with the vertical bar are restored to their normal positions when the bar is later released. Similarly, whenever a horizontal bar is moved, it advances all fingers 32 in a horizontal direction. Since, however, only one of these ngers has been previously elevated, it alone will be effective in the closure of a set of contacts, and the remaining fingers will pass under the corresponding insulating plates, such as plate 4l, without disturbing the associated contactl springs.

With the construction herein. disclosed the asf sembly and repair work on the switch is considerably simplified. The operating fingers 32 can be assembled by merely slipping the tapered end into the receiving slot in. the mounting strip 36 and attaching the retraotile spring 39. In a similar manner any one of these fingers may be Withdrawn at will without disturbing other parts of the switch. Fig. 5 shows one of the fingers in a partially withdrawn position. The operating fingers are made of fairly heavy material and are, therefore, capable of withstanding the wearing action caused by the repeated operation of the bars. Also when released they do not vibrate and return to a point where they are likely to be caught by a bar, operating at that instant, to cause the false closure of contact sets.

What is claimed is:

l. The combination in a switching mechanism of a set of contacts, a supporting member having an aperture therein, a contact operating element with one end loosely fixed in said aperture and supported by said member, means for displacing said element in a plurality of different arcuate movements about its xed end as a center, and means responsive to the movement of said element for operating said contacts.

2. The combination in a switching device of a set of contacts, a supporting member having an aperture therein, a contact operating element supported by said member with one end loosely lixed in said aperture, a spring for holding said element in a normal position relative to said member, means for displacing said element from its normal position in two different arcuate movements about its fixed end as a center, and means responsive to the movement of said element for operating said contacts.

3. The combination in a selective switch of a set of contacts, a supporting member having an aperture therein, a non-iexible contact actuating finger with one end loosely iixed in said aperture and supported by said member, means for displacing said iinger in a plurality of different movements about its iixed end as a center, and means responsive to the movement of said iinger for controlling said contacts.

4. The combination in a selective switch of a set of circuit making contacts, a stationary supporting plate having an opening therein, a rigid actuating finger supported by said plate with one end extending into said opening, means for moving the other end of said iinger in two separate arcuate movements, each in a diiierent plane, and means operated by said iinger for closing said conta/cts.

5. In a selective switch, a set of contacts, a

supporting plate having a slot therein, an actuating element, one end of which projects into said slot and is provided with shoulders which bear against the plate to x said element in its normal position, a spring for holding said element in its normal position, means acting against the tension of said spring for displacing said element from its normal position, and means responsive to the movement of said element for controlling said contact set.

6. In a selective switch, a set of contacts, a supporting plate having a slot therein, a rigid actuating flnger, one end of which extends into said slot and is provided with shoulders which bear against the plate to x said linger in its normal position with respect to said plate, a spring joining the finger and plate for holding said nger in its normal position, means acting against the tension of said spring for displacing said linger in a plurality of directions, and means controlled by the iinger for operating said contacts.

7. In a cross-bar switch, sets of contacts, a

mounting plate having a lineal series of aper-` tures therein, rigid actuating fingers, one for each aperture, each nger having one end loosely iixed in its aperture for free movement in a plurality of directions, springs for holding the respective fingers in position, an operating bar for moving the free ends of said ngers in a line parallel to the line of said apertures, other operating bars for moving the free ends of said lingers at an angle to the line of said apertures, and means controlled by any one of said iingers for operating a corresponding one of said contact sets.

8. The combination in a switching mechanism of a set of circuit contacts, a supporting member, a contact operating iinger, rigid throughout its length and having one of its ends detachably mounted on said supporting member for universal movement with respect thereto, resilient means for holding said finger against detachment from said supporting member, operating means for moving said finger in a plurality of directions, and means responsive to the movement of said nger for operating said set of contacts.

9. The combination in a switch of a set of circuit making contacts, a stationary supporting member, a rigid contact operating nger having one end loosely and detachably mounted on said stationary member for universal movement with respect thereto, resilient means for holding said ringer in its normal position and for preventing its detachment from said supporting member, operating means for moving said finger in a plurality of directions, and means responsive to the movement of said linger for operating said contact set.

10. The combination in a switching device of a set of circuit making contacts, a stationary supporting plate, a rigid con-tact operating nger detachably engaging said plate and sup-ported thereby for universall movement with respect thereto, a spring interconnecting said plate and finger for holding said nger in its normal position and for preventing its disengagement from said plate, selective means for displacing said finger in a plurality of directions, and means responsive to the movement of said linger for operating said set of contacts.

11. The combination in a switching mechanism of a set of contacts, a stationary supporting member, a rigid contact operating element having one end mounted on said supporting member for universal movement with respect thereto, means for displacing the free end of said element in a plurality of different movements, and means responsive to the movement of said element for operating said contacts.

l2. The combination in a switch oi`a set of contacts, a stationary supporting member, a contact operating element mounted on said stationary support for movement in all directions with respect to said support, said element being rigid throughout its length, means for moving said element, means responsive to the movement of said element for operating said set of contacts, and means for restoring said element to its normal position.

13. The combination in a switch of a set of contacts, a stationary supporting member, a contact operating ringer, rigid throughout its length,

. and having one of its ends loosely mounted on said supporting member for universal movement with respect thereto, operating means for moving said finger in a plurality of directions, and means responsive to the movement of said finger for operating said set of contacts.

OSCAR F. FORSBERG. 

